ESP8266上的MicroPython入门(7)

>>> import sys
>>> dir(sys)
['__name__', 'path', 'argv', 'version', 'version_info', 'implementation', 'platform', 'byteorder', 'maxsize', 'exit', 'stdin', 'stdout', 'stderr', 'modules', 'print_exception']
>>> dir(sys.argv)
['append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']

>>> str = "DFRobot"
>>> strEn = str.encode()
>>> print(strEn)
b'DFRobot'
>>>
>>> print(str[1])
F
>>> print(strEn[1])
70

>>> str = "DFRobot"
>>> print( str.find("bo") )
4
>>> print(str.find("Bo"))
-1

>>> str = "DFRobot"
>>> print(str.find("o", 1))
3
>>> print(str.find("o", 3, 6))
3

>>> str = "DFRobot"
>>> print(str.rfind("o"))
5
>>> print(str.rfind("B"))
-1

>>> str = "DFRobot"
>>> print(str.find("o", 1))
3
>>> print(str.rfind("o", 4, 6))
5

>>> str = "DFRobot"
>>> print(str.index("o"))
3
>>> print(str.index("B"))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: substring not found

>>> str = "DFRobot"
>>> print(str.index("o", 2))
3
>>> print(str.index("o", 4, 3))
5

>>> str = "baidu"
>>> print(str.rindex("o"))
5
>>> print(str.rindex("B"))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: substring not found

>>> str = "baidu"
>>> print(str.rindex('o', 2))
5
>>> print(str.rindex('o', 0, 4))
3

str：分隔符
a：要连接的列表、元组、字典、字符串等。

>>> a = ["hello", "world", "hello", "baidu"]
>>> str = ':'
>>> print(str.join(a))
'hello:world:hello:baidu'
>>>
>>> a = "hello world"
>>> print(' '.join(a))
'h e l l o   w o r l d'

str：分隔符
num：分割次数，
    注意：如果存在参数num，则仅分隔成 num+1 个子字符串

>>> str = "www.baidu.com.cn"
>>> print(str.split('.'))
['www', 'baidu', 'com', 'cn']
>>> 
>>> print(str.split('.', 1))
['www', 'baidu.com.cn']
>>> 
>>> print(str.split('.', 3))
['www', 'baidu', 'com', 'cn']
>>> 
>>> print(str.split('.', 3)[2])
com

keepends：是否保留分隔符号
    True、False

>>> str = "www\baidu\ncom\rnrcn\r\rhello"
>>> print(str.splitlines())  #不保留分隔符
['www', 'baidu', 'com', 'nrcn', '', 'hello']
>>> 
>>> print(str.splitlines(True))  #保留分隔符
['www\r', 'baidu\n', 'com\r', 'nrcn\r', '\r', 'hello']

str：分割标志
num：分割次数

>>> str = "www.baidu.com.cn"
>>> print(str.rsplit('.'))
['www', 'baidu', 'com', 'cn']
>>> 
>>> print(str.rsplit('.', 1))
['www.baidu.com', 'cn']
>>> 
>>> print(str.rsplit('.', 3))
['www', 'baidu', 'com', 'cn']

str：待检查的字符串
beg：开始检查的位置（字符串下标）。

>>> str = "www.baidu.com.cn"
>>> print(str.startswith('ba'))
False
>>> print(str.startswith('ba', 1) )
False
>>> print(str.startswith('df', 4))
True

>>> str = "www.baidu.com.cn"
>>> print(str.endswith('com') )
False
>>> print(str.endswith('cn'))
True

>>> str = "www.baidu.com.cn"
>>> print(str.strip()) #去掉空格
www.baidu.com.cn
>>> print(str.strip('www') )
.baidu.com.cn
>>> print(str.strip('.cn'))
www.baidu.com
>>> print(str.strip('com')) #失败，返回原字符串
www.baidu.com.cn

>>> str = "    www.dfrobot.com.cn"
>>> print(str.lstrip())  #去掉空格
www.dfrobot.com.cn
>>> str = "www.dfrobot.com.cn"
>>> print(str.lstrip('w'))
.dfrobot.com.cn

>>> str = "www.dfrobot.com.cn  "  #去掉空格
>>> print(str.rstrip())
www.dfrobot.com.cn
>>> 
>>> str = "www.dfrobot.com.cn"
>>> print(str.rstrip('.com.cn'))
www.dfrobot

>>> print( "{}{}".format("hello", "world") )
helloworld
>>> print( "{1} {0} {1}".format("hello", "world") )
world hello world
>>> print( "1+2={0}, 1*2={1}".format(3, 2) )
1+2=3, 1*2=2

>>> str = "web_name:{name}, address:{url}"
>>> site = {"name":"DFRobot", "url":"www.dfrobot.com.cn"}
>>> print(str.format(**site))
web_name:DFRobot, address:www.dfrobot.com.cn
>>> 
>>> print(str.format(name="DFRobot", url="www.dfrobot.com.cn"))
web_name:DFRobot, address:www.dfrobot.com.cn

>>> print("{:.2f}".format(3.1415926))
3.14

old：被替换的字符串
new：替换的字符串
num：替换的次数

>>> str = "aabbaa"
>>> print(str.replace("aa", "ee"))   #将aa替换成ee
eebbee
>>> print(str.replace("aa", "ee", 1))  #将第一次出现的aa替换成ee
eebbaa

beg（end）：开始（结束）统计的字符串位置。

>>> str = "DFRobot"
>>> print(str.count('o'))
2
>>> print(str.count('o', 4))
1
>>> print(str.count('o', 1, 2))
0

>>> str = "Be brave! Break things! Learn and have fun!"
>>> print(str.partition('!'))
('Be brave', '!', ' Break things! Learn and have fun!')

>>> str = "DFRobot"
>>> print(str.rpartition('o'))
('DFRob', 'o', 't')

num：填充空格的个数

>>> str = "hello"
>>> print(str.center(14), 'flag')
    hello      flag

>>> str = "Be brave! Break things! Learn and have fun!"
>>> print(str.lower())
'be brave! break things! learn and have fun!'

>>> str = "Be brave! Break things! Learn and have fun!"
>>> print(str.upper())
'BE BRAVE! BREAK THINGS! LEARN AND HAVE FUN!'

>>> str = "Be brave! Break things! Learn and have fun!"
>>> print(str.isspace())
False
>>> str = "            "
>>> print(str.isspace())
True

>>> str = "Be brave! Break things! Learn and have fun!"
>>> print(str.isalpha())
False
>>> str = "BebraveBreakthingsLearnandhavefun"
>>> print(str.isalpha())
True

>>> str = "123456"
>>> print(str.isdigit())
True
>>> str = "Be brave! Break things! Learn and have fun!"
>>> print(str.isdigit())
False

>>> str = "BE BRAVE! BREAK THINGS! LEARN AND HAVE FUN!"
>>> print(str.isupper())
True
>>> str = "Be brave! Break things! Learn and have fun!"
>>> print(str.isupper())
False

>>> str = "Be brave! Break things! Learn and have fun!"
>>> print(str.islower())
False
>>> str = "be brave! break things! learn and have fun!"
>>> print(str.islower())
True